gopls/internal/analysis/modernize: remove SortStable

Remove the modernization from sort.SliceStable to slices.SortStable.

There is no slices.SortStable.

Change-Id: I55e6c6848aa2708976d35ceabab73e7b55da1d1f
Reviewed-on: https://go-review.googlesource.com/c/tools/+/647735
Reviewed-by: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

Author: jba

gopls/internal/analysis/modernize/sortslice.go

@@ -9,7 +9,6 @@ import (
 	"go/ast"
 	"go/token"
 	"go/types"
-	"strings"
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/inspect"
@@ -25,13 +24,15 @@ import (
 //		sort.Slice(s, func(i, j int) bool { return s[i] < s[j] })
 //	  =>	slices.Sort(s)
 //
-// It also supports the SliceStable variant.
+// There is no slices.SortStable.
 //
 // TODO(adonovan): support
 //
 //   - sort.Slice(s, func(i, j int) bool { return s[i] ... s[j] })
-//     -> slices.SortFunc(s, func(x, y int) bool { return x ... y })
-//     iff all uses of i, j can be replaced by s[i], s[j].
+//     -> slices.SortFunc(s, func(x, y T) int { return x ... y })
+//     iff all uses of i, j can be replaced by s[i], s[j] and "<" can be replaced with cmp.Compare.
+//
+//   - As above for sort.SliceStable -> slices.SortStableFunc.
 //
 //   - sort.Sort(x) where x has a named slice type whose Less method is the natural order.
 //     -> sort.Slice(x)
@@ -43,13 +44,11 @@ func sortslice(pass *analysis.Pass) {
 	info := pass.TypesInfo
 
 	check := func(file *ast.File, call *ast.CallExpr) {
-		// call to sort.Slice{,Stable}?
+		// call to sort.Slice?
 		obj := typeutil.Callee(info, call)
-		if !analysisinternal.IsFunctionNamed(obj, "sort", "Slice", "SliceStable") {
+		if !analysisinternal.IsFunctionNamed(obj, "sort", "Slice") {
 			return
 		}
-		stable := cond(strings.HasSuffix(obj.Name(), "Stable"), "Stable", "")
-
 		if lit, ok := call.Args[1].(*ast.FuncLit); ok && len(lit.Body.List) == 1 {
 			sig := info.Types[lit.Type].Type.(*types.Signature)
 
@@ -78,15 +77,15 @@ func sortslice(pass *analysis.Pass) {
 						Pos:      call.Fun.Pos(),
 						End:      call.Fun.End(),
 						Category: "sortslice",
-						Message:  fmt.Sprintf("sort.Slice%[1]s can be modernized using slices.Sort%[1]s", stable),
+						Message:  fmt.Sprintf("sort.Slice can be modernized using slices.Sort"),
 						SuggestedFixes: []analysis.SuggestedFix{{
-							Message: fmt.Sprintf("Replace sort.Slice%[1]s call by slices.Sort%[1]s", stable),
+							Message: fmt.Sprintf("Replace sort.Slice call by slices.Sort"),
 							TextEdits: append(importEdits, []analysis.TextEdit{
 								{
 									// Replace sort.Slice with slices.Sort.
 									Pos:     call.Fun.Pos(),
 									End:     call.Fun.End(),
-									NewText: []byte(slicesName + ".Sort" + stable),
+									NewText: []byte(slicesName + ".Sort"),
 								},
 								{
 									// Eliminate FuncLit.

gopls/internal/analysis/modernize/testdata/src/sortslice/sortslice.go

@@ -6,8 +6,6 @@ type myint int
 
 func _(s []myint) {
 	sort.Slice(s, func(i, j int) bool { return s[i] < s[j] }) // want "sort.Slice can be modernized using slices.Sort"
-
-	sort.SliceStable(s, func(i, j int) bool { return s[i] < s[j] }) // want "sort.SliceStable can be modernized using slices.SortStable"
 }
 
 func _(x *struct{ s []int }) {

gopls/internal/analysis/modernize/testdata/src/sortslice/sortslice.go.golden

@@ -4,16 +4,12 @@ import "slices"
 
 import "slices"
 
-import "slices"
-
 import "sort"
 
 type myint int
 
 func _(s []myint) {
 	slices.Sort(s) // want "sort.Slice can be modernized using slices.Sort"
-	
-	slices.SortStable(s) // want "sort.SliceStable can be modernized using slices.SortStable"
 }
 
 func _(x *struct{ s []int }) {